The nacelle and thrust reverser panels used on commercial airplane applications are derived from a series of lofted surfaces to manage air as it flows around, and is passed through high by-pass turbofan engines. Of primary interest are the fan duct contours, that for purposes of this application can be described as the inner fan duct surface and the outer fan duct surface. These two opposing surfaces are faced with an upper and lower surface that are also lofted but could be represented by a near vertical intersecting plane. These four surfaces create the fan-duct cavity which could be simplistically described in a shape that are two half circles, one larger than the other, with their ends connected with two vertical lines.
Presently it is known to fabricate fan duct panels by individually forming the required sides of the fan duct that correlate to the individually lofted surfaces, each surface requiring an individual tool, and then subsequently attaching them together via rivets, to form a completed fan duct geometry. There are a number of disadvantages inherent in known methods of fabricating fan duct panels requiring tools discretely allocated to each lofted surface. One disadvantage is that there are multiple tools allocated to each lofted surface, which require multiple cure stages during part fabrication that contribute to increased expense and flow-time of the process. Since multiple tooling is required for each specific lofted surface, another disadvantage is the significant weight of the fan duct tooling.
The known tools, due to their significant weight, are bulky and require substantial capital equipment to move them around. The inherent weight of the known tooling also causes great concern for deflection during handling. Since the lofted contours that the tools are supposed to replicate have to be kept to extremely tight tolerances, the tools have to be designed for deflections using open sections that are extremely structurally inefficient. The result is that even more weight is added to compensate for tool deflection issues. An additional disadvantage relating to the deflection issue is that the known tooling has to lie flat on the floor and workers are unable to stand while performing part fabrication. Therefore, workers are required to bend and to climb over them. The result of this is worker exhaustion and attrition. Yet another disadvantage of this type of tool configuration in the state of the art is the significant waste of the composite materials used to form the part due to tool excess surface requirements, which accommodate the vacuum bag for part cure. Finally, other disadvantages include the great expense associated with the tool fabrication of the known tooling, the fabrication of individual fairing bars for the known tooling which can constitute a substantial number of individual components, and the individual time and labor to place and remove these fairing bars on the tool during part fabrication.